99 ram 1500 4x4
5.2

plenum just replaced in june

The trucks been acting funny lately...not speeding up anymore past 4000 rpms...
Thought it was a tranny

but then today, i was driving down the road, and engined just revved and check engine like flashed.
checked teh codes, multiple/random cylinder misfires. Checked twice and all 8 were misfiring at some point.

cant get it above 2500 RPMs or itll just stutter and check engine light will flash.

Any other ideas?


99,917 miles on it now

60,000 pulling horse trailers.

cat's been tested...whole exhaust system is in good shape.
New plugs/wires/cap.
new tranny filter/gasket

any ideas?
after replacing the tranny filter, got it out on the road again to test it...same results past 3000rpms, but its misfiring cylinders 4 and 7 the most...

 

Check your Fuel Pressure. Should be around 50 Psi.

Is it possible you got a tank of crappy gas and it plugged your injectors?

 

how do I check fuel pressur?

 

The other issue if that it only does it in gear.

Nuetral and Park dont have any problems. Could that still be a fuel filter/pump issue

 

You need a fuel pressure gauge.
It screws on to a test port on the fuel rail.
You might be able to borrow one from your local parts store.

 

the same exact thing happend to my 99 ram (5.9) this weekend.let me know if you find anything and i'll do the same

 

Check the fuel pressure, and also have the cat. checked.

 

Sure sounds like a plugged cat.How did you check it?Delta test?

 

Might be computer mlfcn. Almost sounds electrical.